Motor control device and motor control method

ABSTRACT

A motor control device includes a current command value calculating device calculating a basic current command value, a first compensation device compensating for a delay in the rotor magnetic flux response of the motor by amplifying the basic current command value, a first current command value limiting device for restricting a post-compensation current command value by a first current limiting value, a second compensation device calculating a compensation value for the amplified current command value, an adding device calculating the post-compensation current command value by adding the amplified current command value and the compensation value, and motor control device controlling the motor, the second compensation device calculating, as the compensation value, a command value corresponding to a portion limited by the first current limiting value of the amplified current amplification command value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National stage application of InternationalApplication No. PCT/JP2014/052737, filed Feb. 6, 2014, which claimspriority to Japanese No. 2013-035637 filed in Japan on Feb. 26, 2013,the contents of each of which is hereby incorporated herein byreference.

BACKGROUND

1. Field of the Invention

The present invention relates to a motor control device and a motorcontrol method.

2. Background Information

A motor control system is disclosed in JP H8-163900 A, which includes anexcitation current command value calculating unit for calculating anexcitation current command value for generating a target magnetic fluxin an induction motor control device and an excitation current limiterunit for limiting the positive and negative excitation current commandlimit values, wherein the excitation current command value calculatingunit calculates the excitation current command value so as tosignificantly change the value of the excitation current in order tochange the response of a secondary magnetic flux. In addition, theexcitation current limiter sets the limit values to prevent excessivecurrent from being supplied in order to protect the driving circuit ofan inverter (JP H8-163900 A).

SUMMARY

However, in the above motor control device, in order to increase theresponsiveness of the magnetic flux, in response to applying atransiently large excitation current, when the exciting current has beenlimited by an upper limit value representing a constant maximumallowable current, the amount of the excitation current which has beensubject to restriction or limit would not flow. Thus, a problem arisesand torque responsiveness deteriorates due to insufficient rotor flux.

An object of the present invention intends to solve is to provide amotor control device or a motor control method to improve the responseof the torque.

The problem described above is solved, according to the presentinvention, by amplifying a base current command value based on a torquecommand value to compensate for the delay of the rotor flux response ofthe motor, by limiting or restricting a post-compensation command valueby a first current limit value, by calculating a compensation value forthe amplified current command value based on the amplified currentcommand value and the first restricted current command value, and byadding the amplified current command value and the compensation value tocalculate the post-compensation command value. In addition, bycalculating a portion or amount of the amplified current command valuewhich has been subject to restriction by the first current limit valueas the compensation value, the object described above will be solved.

According to the present invention, when the amplified current commandvalue for compensating for delay in the rotor flux response has beensubject to a current limit value, by adding the restricted portion ofthe current command value to the amplified current command value as thecompensation value, after the amplified current command value reaches avalue which is not subject to restriction by the current limit value,the amplified current command value is compensated for by thecompensation value so that it is possible to improve the responsivenessof the torque.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure.

FIG. 1 is a block diagram of an electric vehicle system of an embodimentaccording to the present invention;

FIG. 2 is a graph for illustrating a map referred to by a motor torquecontrol unit in FIG. 1, which shows a correlation of a motor rotationspeed and a torque command value for each accelerator opening;

FIG. 3 is a block diagram of the current control unit in FIG. 1;

FIG. 4 is a block diagram of a current command value calculating unit inFIG. 3;

FIG. 5 is a block diagram of an excitation current compensation controlunit of FIG. 4;

FIG. 6 is a block diagram of a torque current compensation control unitof FIG. 4;

FIG. 7 is a flowchart showing a control procedure of the motorcontroller in FIG. 1;

FIG. 8 is a flow chart showing the control procedure of step 4 in FIG.7;

FIG. 9 is a flow chart showing a control procedure of step S45 in FIG.8;

FIGS. 10A-10D are graphs showing a torque response of the motorcontrolled by a motor control device pertaining to a comparativeexample;

FIGS. 11A-11D are graphs showing a torque response of the motorcontrolled by a motor control device according to the present invention;

FIG. 12 is a block diagram of an excitation current compensation controlunit of the motor control device in another embodiment according to thepresent invention;

FIG. 13 is a block diagram of a torque current compensation control unitof the motor control device in an embodiment according to the presentinvention.

FIG. 14 is a block diagram of an excitation current compensation controlunit of the motor control device in a yet another embodiment accordingto the present invention; and

FIG. 15 is a block diagram of a torque current compensation control unitof the motor control device in the yet another embodiment according tothe present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a description is given of embodiments according to thepresent invention with reference to the drawings.

First Embodiment

FIG. 1 is a block diagram showing the configuration of an electricvehicle system equipped with a motor control device pertaining to anembodiment according to the present invention. Below, althoughdescription is given by referring to an example in which the motorcontrol device according to the present embodiment is applied to theelectric vehicle, the present motor control device is equally applicableto other vehicles than the electric vehicle such as a hybrid electricvehicle (HEV).

As shown in FIG. 1, a vehicle which includes a motor control device ofthis embodiment includes a battery 1, an inverter 2, a motor 3, a speedreduction unit 4, a drive shaft (driving shaft) 5, driving wheels 6, 7,a voltage sensor 8, a current sensor 9, a rotation sensor 10, and amotor controller 20.

The battery 1 represents a power source of the vehicle and is formed byconnecting a plurality of secondary batteries in series or parallel. Aninverter 2 includes a power conversion circuit in which a plurality ofswitching elements, such as IGBT or MOSFET, is provided, such that twoof these are connected for each phase. The inverter 2, by switching ONand OFF the switching elements in response to a drive signal from themotor controller 20, converts the DC power outputted from the battery 1into AC power for outputting to the motor 3. Thus, the motor 3 is drivenby flow of a desired current. Also, the inverter 2 inversely convertsthe AC power output by regeneration of the motor 3 for outputting to thebattery 1.

The motor 3 represents a drive source of the vehicle and is configuredin an induction motor for transmitting a driving force to driving wheels6, 7 via a reduction unit 4 and the drive shaft 5. The motor 3 rotatesjointly with the driving wheels 6 and 7, and, by generating aregenerative driving force, recovers the kinetic energy of the vehicleas electrical energy. Thus, the battery 1 is discharged by the drivingoperation of the motor 3, while being charged by the regenerativeoperation of the motor 3.

The voltage sensor 8 is a sensor for detecting the voltage of thebattery 1, and is connected between the battery 1 and the inverter 2.The detection voltage of the voltage sensor 8 is output to the motorcontroller 20. The current sensor 9 is a sensor for detecting thecurrent of the motor 3, and is connected between the inverter 2 and themotor 3. The detection current of the current sensor 9 is output to themotor controller 20. The rotation sensor 10 is a sensor for detectingthe rotation speed of the motor 3, and is constituted by a resolver orthe like. The detection value of the rotation sensor 10 is output to themotor controller 20.

The motor controller 20, based on a vehicle speed (V), an acceleratoropening (APO), a rotor phase of the motor 3 (θ_(re)), a motor current, avoltage of the battery 1, and the like, generates a PWM signal foroperating the inverter 2 to output to a drive circuit (not shown) forthe inverter operation. The drive circuit, based on the PWM controlsignal, controls a drive signal of a switching element of the inverter 2for outputting to the inverter 2. Thus, the motor controller 20 drivesthe motor 3 by operating the inverter.

The motor controller 20 is a controller for controlling the motor 3. Themotor controller 20 includes a motor torque control unit 21, a dampingcontrol unit 22, and a current control unit 23.

The Motor torque control unit 21, based on a signal of the vehicleinformation indicating the vehicle variables to be inputted to the motorcontroller 20, calculates a torque command value (T_(m1)*) correspondingto a required torque in response to a user operation or a systemrequirement for outputting to the damping control unit 22.

In the motor torque control unit 21, a torque map showing therelationship of FIG. 2 is stored in advance. FIG. 2 is a graph showingthe correlation of the motor rotation speed and the basic target torquecommand value in each accelerator opening. The torque map is previouslyset as the relationship of the torque command value with respect toaccelerator opening for each accelerator opening. The torque map is setwith the torque command value such that, with respect to the acceleratoropening and the motor rotation speed, torque may be output efficientlyfrom the motor 3.

The motor rotation speed is calculated based on the detection value ofthe rotation sensor 10. The accelerator opening is detected by anaccelerator opening sensor (not shown). The motor torque control unit 21refers to the torque map, and calculates a base target torque commandvalue (T_(m1)*) corresponding to the input accelerator opening (APO) andthe motor rotation speed for outputting to the damping control unit 22.When a shift lever is set to a parking position or the neutral position,the base target torque command value (T_(m)*) becomes zero.

Note that the base target torque command value (T_(m1)*) is notnecessarily calculated by the accelerator opening and the motor speedonly. A vehicle speed and the like may be added for calculation, forexample. The vehicle speed V [km/h] may be obtained in the communicationwith a meter, a brake controller, or the like. Alternatively, thevehicle speed may be obtained by first multiplying a tire dynamic radius(R) to a rotor mechanical angular velocity (ω rm), and the dividing by agear ratio of the final gear to obtains a vehicle speed v [m/s], andfurther multiplying a unit conversion coefficient (3600/1000) forconversion from the unit [m/s] to the unit [km/h].

The damping control unit 22 receives the basic motor torque commandvalue T_(m1)* and the motor rotation speed N_(m) as input, and, withoutsacrificing the response of the drive shaft torque, calculates apost-damping torque command value T_(m2)* which suppresses the vibrationof the power transmission system torque caused by torsional vibration ofthe drive shaft 5 (driving shaft). Fore detailed control of the dampingcontrol unit 22, for example, see Japanese Patent ApplicationPublications (JP No. 2001-45613A and JP No. 2003-9559 A). Further, thedamping control unit 22 output the post-damping torque command valueT_(m2) to the current control unit 23. Note that the damping controlunit 22 is not necessarily required.

Returning back to FIG. 1, the current control unit 23 represents acontrol unit that controls a current flowing through the motor 3 basedon the torque command value (T_(m2)*). Below, with reference to FIG. 3,a description is given of a configuration of the current control unit23. FIG. 3 is a block diagram of the current control unit 23, thebattery 1, and the like.

The current control unit 23 includes a current command value calculatingunit (or device) 30, a subtracting unit 41, a current FB control unit42, a coordinate system converter 43, a PWM converter 44, an ADconverter 45, a coordinate system converter 46, a pulse counter 47, anangular velocity calculating unit 48, a slip angle velocity calculatingunit 49, a power source phase calculating unit 50, and a motor rotationspeed calculating unit 51.

The current command value calculator 30 receives a post-damping torquecommand value (T m2*) input from the damping control unit 22, therotation speed (Nm) input from the motor rotation speed calculating unit51, and the detection voltage (Vdc) of the voltage sensor 8 forcalculating and outputting γδ-axis current command values (I γ*, I δ*).Here, the γδ-axes show the components of the rotating coordinate system.

The subtracting unit 41 calculates differences between the γδ-axiscurrent command values (I γ*, I δ*) and the γδ-axis current (*I γ, I δ*)to output to the current FB control unit 42. The current FB control unit42 performs a feedback control such that the γ-axis current (I γ) andthe δ-axis current (I δ) respectively match the γ-axis command value (Iγ*) and δ-axis command value (I δ*). The current FB controller 42controls and calculates such that the γδ-axis current (I γ, I δ) followsthe γδ-axis current command values at a predetermined response withoutsteady deviation or difference, and outputs the voltage command valuesof the γδ axes (v γ*, v δ*) to the coordinate converter 43. Note thatthe γ-axis current represents an excitation current of the motor 3,while the δ axis current represents a torque current of the motor 3.Moreover, the non-interference control may be added to control thesubtracting unit 41 and the current FB control unit 42.

The coordinate converter 43 receives the γδ-axis voltage command values(v γ*, v δ*) and the power supply phase (θ) calculated by the powersource phase calculating unit 50, and converts the γδ-axis voltagecommand values (v γ*, v δ*) to u, v, w-axis voltage command values in afixed coordinate system (v u*, v v*, vw*) for outputting to the PWMconverter 44.

The PWM converter 44, based on the input voltage command values (V u*, Vv*, V w*), generates switching signals of the switching elements of theinverter 2 (D*uu, D*ul, D*vu, D*vl, D*wu, D*wl) for outputting to theinverter 2.

The A/D converter 45 samples the phase current (I u, I v) indicatingdetection values of the current sensor 9, and outputs the sampled phasecurrent (I us, I vs) to the coordinate converter 46. Since the sum ofthe current values of the three phases is zero, the w-phase current isnot detected by the current sensor 9. Alternatively, the coordinateconverter 46 calculates the phase current of the w phase (I ws) based onthe input phase current (I us, I vs). Note that, with respect to the wphase current, a current sensor 9 may be disposed in the w phase forcurrent detection.

The coordinate converter 46 is intended for performing a three-phase totwo-phase conversion, and, using a supply power phase (θ), converts thephase current of the fixed coordinate system (I us, I vs, I ws) to γδaxis current of the rotating coordinate system (I γs, I δs) foroutputting to the subtracting unit 41. Thus, the current value detectedby the current sensor 9 is fed back.

The pulse counter 47, by counting the pulses output from the rotationsensor 10 to obtain a rotor phase (θ re) (electrical angle) indicatingposition information of the motor 3 for outputting to the angularvelocity calculating unit 48.

The angular velocity calculating unit 48 performs a differentialoperation of the rotor phase (θ re) to calculate the rotor angularvelocity (ω re) (electrical angle) for outputting to the power supplyphase calculating unit 50. Further, the angular velocity calculatingunit 48, by dividing the calculated rotor angular velocity (ω re) by thenumber of pole pairs p of the motor 3 to calculate a rotary mechanicalangular velocity of the motor (ω rm) [rad/s] for outputting to the motorrotation speed calculating unit 51.

The slip angular velocity calculating unit 49 calculates a rotor fluxestimation value (φ Est) considering a rotor flux response delay withrespect to the excitation current command value

(I γ*) by the following equation (1):

$\begin{matrix}{\phi_{est} = {\frac{M}{{\tau_{\phi}s} + 1}I_{\gamma}^{*}}} & (1)\end{matrix}$Wherein, M indicates the mutual inductance, and τ φ is the response timeconstant of the rotor flux. In addition, τ φ is represented by Or/Rr,wherein Or is the self-inductance of the rotor, and Rr indicates therotor resistance.

Further, the slip angular velocity calculating unit 49, as representedby the equation (2), calculates a slip angular velocity (ω se) bydividing the ratio of the torque current command value (I δ*) to therotor flux estimate (φ Est) obtained from equation (1), by a constantdetermined by the characteristics of the motor.

$\begin{matrix}{\omega_{se} = {\frac{M \cdot R_{r}}{L_{r}} \cdot \frac{I_{\delta}^{*}}{\phi_{est}}}} & (2)\end{matrix}$Note that these values, M, τ φ, M·Rr/Lr and the like may be used bycalculating or experimentally obtaining for storing in a table inadvance with respect a rotor temperature, a current value, and thetorque command value.

Further, the slip angular velocity calculating unit 49 outputs to thepower supply phase calculating unit 50 the slip angular velocity (ω se).Thus, by setting the slip angular velocity (ω se), the output torquewill be handled by the product of the torque current and the rotor flux.

Further, the power supply phase calculating unit 50, as shown in thefollowing equation (3) below, by adding the slop angular velocity (ω se)to the rotor angular velocity (ω re) (electrical angle) and integratingthe sum to calculate a power supply phase (θ) for outputting to thecoordinate converters 43, 46.

$\begin{matrix}{\theta = {\frac{1}{s}\left( {\omega_{re} + \omega_{se}} \right)}} & (3)\end{matrix}$

The motor rotation speed calculating unit 51 calculates a motor rotationspeed (Nm) by multiplying the coefficient (60/2π) for the unitconversion from [rad/s] to [rpm] with the rotor mechanical angularvelocity (ω rm) for outputting to the current command value calculatingunit 30.

Now, a description of the configuration of the current command valuecalculating unit 30 is given with reference to FIG. 4. FIG. 4 is a blockdiagram showing the configuration of a current command value calculatingunit 30. The current command value calculating unit 30 includes a basecurrent command value calculating unit 31, a magnetic flux responsecompensation unit 32, an excitation current command value change amountcalculating unit 33, a compensation determining unit 34, and acompensation control unit 35.

In the base current command value calculating unit 31, a map is storedin advance showing a relationship between basic γδ-axis current commandvalues (I γ0*δ0*) with respect to a post-damping control torque commandvalue (T m2*), the voltage of the battery 1 (V dc) and the motor speed(N m). The basic γδ-axis current command values (I γ0*, I δ0*) representa current command value which is obtainable through experiment orcalculations for optimization of the overall efficiency of the inverter2 and the motor 3 with respect to the post-damping control torquecommand value (T m2*), the voltage of the battery 1 (V dc) and the motorspeed (N m). Further, the basic current command value calculating unit31 refers to the map and calculates the basic γδ-axis current commandvalues (I γ0*, I δ0*) corresponding to the post-damping control torquecommand value (T m2*), the voltage of the battery 1 (V dc) and the motorspeed (N m) for outputting to the magnetic flux response compensationunit 32 and the excitation current command change amount calculatingunit 33.

The flux response compensation unit 32 is intended to calculate at leastone current command value of the flux compensation γ-axis current value(I_(γ1)*) and the flux compensation δ-axis current value (I_(δ1)*) toamplify the basic current command value by advancing the lag phase inorder to compensate for the rotor flux delay.

In general, the response of the rotor flux is lower by one or moredigits as compared to the response of the torque current. Further, theoutput of the motor 3 is proportional to the product of the rotor fluxand torque current of the stator. Therefore, due to the response delayof the rotor flux, the torque response is delayed. The flux responsecompensation unit 32 compensates the current command value to compensatefor the delay in such torque response. Thus, since the motor 3 may besupplied with a transiently large exciting due to increase in the basecurrent command value, it is possible to improve torque responsivenesswhile improving the rotor flux response.

The flux response compensation unit 32, as indicated by the followingequation (4), by multiplying the basic γ-axis current command value (Iγ0*) with a coefficient containing a response time constant of thestator current (τ i) and a response time constant of the rotor flux (τφ), calculates a flux compensation γ-axis current command value (I γ1*)for outputting to the compensation control unit 35.

$\begin{matrix}{I_{\gamma\; 1}^{*} = {\frac{{\tau_{\phi}s} + 1}{{\tau_{i}s} + 1}I_{\gamma\; 0}^{*}}} & (4)\end{matrix}$

Between the response time constant of the stator current (τ i) and theresponse time constant of the rotor flux (T_(φ)), the relationship of τi<τ φ is satisfied. Therefore, the magnetic flux responsive compensationunit 32 uses equation (4) and calculates the flux compensation γ-axiscurrent command value (I γ1*) to function as a phase advancecompensator.

Also, the flux responsive compensating unit 32, when improving theresponse of the torque current, multiplies the base δ-axis current value(I δ0*) with a function including the response time constant of thestator current (T i) and a response time constant of the rotor flux (τφ)to calculate the magnetic flux compensation δ-axis current command value(I δ1*) for outputting to the compensation control unit 35. Thearithmetic expression for the flux compensation δ-axis current value (Iδ1*) is represented by the following equation (5).

$\begin{matrix}{I_{\delta\; 1}^{*} = {\frac{{\tau_{\phi}s} + 1}{{\tau_{i}s} + 1}I_{\delta\; 0}^{*}}} & (5)\end{matrix}$

The excitation current command value change amount calculating unit 33uses the approximate equation of the following formula (6), andcalculates a change amount (dI γ0*) in the basic γ-axis current commandvalue from the input basic γ-axis current value (I γ0*), for outputtingto the compensation determining unit 34.

$\begin{matrix}{{dI}_{\gamma\; 0}^{*} = {\frac{s}{{\tau_{0}s} + 1}I_{\gamma\; 0}^{*}}} & (6)\end{matrix}$Wherein τ 0 represents a set value indicating the length of time inwhich the change in the basic γ-axis current value (I γ0*) isapproximately calculated, and is obtainable through design orexperiments in advance,

Note that the amount of change (dI γ0*) may also be obtained bycalculating the difference between the basic γ axis current value of theprevious calculation (I γ0*) and the basic γ axis current value at thecurrent calculation (I γ0*). The calculating unit such as the currentcommand value calculating unit 30 and the like included in the motorcontroller 20 calculate the command value and the like at apredetermined control cycle. The command value of previous calculationdenotes a command value which has been calculated at an earlier timingby the predetermined control cycle than the command value of the currentcalculation.

The compensation determination unit 34 compares the amount of change inthe basic γ axis current command value (dI γ0*) with a determinationthreshold value (I 0), and based on the comparison result, to determinewhether to perform additional compensation for the excitation current orto perform additional compensation for the torque current.

In the present embodiment, while compensating for either the excitationcurrent or the torque current at the flux response compensation unit 32,the compensation control unit 35 performs an additional compensation. Inaddition, depending on the change amount in the excitation currentcommand value, the compensation control unit 35 selectively performs thecompensation for higher torque responsiveness through the excitationcurrent or the torque current. Therefore, the compensation determinationunit 34, in order to select a compensation target at the compensationcontrol unit 35, performs a comparison between the change amount WI γ0*)and the determination threshold value (I 0) for outputting thecomparison result to the compensation control unit 35.

The determination threshold (I 0) determines whether to carry out anadditional compensation on the excitation current or the torque current,and is a previously set threshold obtained either through designconsideration or through experiments.

When the amount of change in the basic γ axis current command value (dIγ0*) is greater than the determination threshold (I 0), the compensationdetermination unit 34 determines that the excitation current changes andtransmits a signal to the compensation control unit 35 requesting forallowing an additional compensation for the excitation current toenhance the response speed.

On the other hand, when the amount of change in the basic γ axis currentcommand value (dI γ0*) is equal to the determination threshold (I 0) orless, the compensation determination unit 34 transmits a signal to thecompensation control unit 35 requesting for allowing an additionalcompensation for torque current since the amount of change in theexcitation current is small and thus it is not necessary for theresponse speed of the excitation current to be enhanced,

The compensation control unit 35 is intended to serve a control unitthat, in order to increase the response speed of the torque, based onthe determination result of the compensation determination unit 34,selectively performs an additional compensation for the excitationcurrent and an additional compensation for the torque current. Thecompensation control unit 35 includes an excitation current compensationcontrol unit 100 and a torque current compensation control unit 200.

When the compensation determination unit 34 allows the additionalcompensation for the excitation current, the compensation control unit35 controls the excitation current compensation control unit 100 toperform a control to increase the torque response speed. The excitationcurrent compensation control unit 100 calculates γδ-axis current commandvalue (I γ*, I δ*) based on the flux compensation γ-axis current commandvalue (I γ1*) compensated by the flux response compensation unit 32, thebasic δ-axis current value (I δ0*), and post-damping control torquecommand value (T m2*) for outputting to the subtractor 41 and the slipangular velocity calculating unit 49.

When the compensation determination unit 34 allows the additionalcompensation for the torque current, the compensation control unit 35controls the torque current compensation control unit 200 to perform acontrol to increase the torque response speed. The torque currentcompensation control unit 200 calculates γδ-axis current command value(I γ*, I δ*) based on the flux compensation δ-axis current command value(I δ1*) compensated by the flux response compensation unit 32, the basicγ-axis current value (Iγ0*), and post-damping control torque commandvalue (T m2*) for outputting to the subtractor 41 and the slip angularvelocity calculating unit 49.

Now, a description of detailed configuration of the excitation currentcompensation control unit 100 with reference to FIG. 5. FIG. 5 is ablock diagram showing the configuration of a magnetic flux responsecompensation unit 32 and the exciting current compensation control unit100.

The excitation current compensation control unit 100 includes a torquecurrent limit section 101, a rotor flux estimation unit 102, an outputtorque estimation unit 103, an ideal response torque calculating unit104, a torque deviation calculating unit 105, an integration resetjudging unit 106, an excitation current command value deviationcalculating unit 107, an additional compensation value calculating unit108, an adder 109, a torque current estimation unit 110, an excitationcurrent limit value calculating unit 111 and an excitation currentlimiting unit 112.

The torque current limiting unit 101 calculates a δ-axis current commandvalue (I δ) by applying a restriction of current limit (±Imax_δ) on theinput basic δ-axis current command value (I δ0*). The current limitvalue (±Imax_δ) is defined by the upper and lower limits, and representthresholds previously set by the design or experiments.

The torque current limiting unit 101, when the basic δ-axis currentvalue (I δ0*) is higher than the upper limit current value of the upperlimit (+Imax_δ), the current limit value (+Imax_δ) is calculated as theδ-axis current command value (I δ). The torque current limiting unit101, when the basic δ-axis current value (I δ0*) is less than the lowerlimit current value (−Imax_δ), the current limit value (−Imax_δ) iscalculated as the δ-axis current value (I δ*). Also, the torque currentlimiting unit 101, when the basic δ-axis current value (I δ0*) is higherthan the lower limit current limit value (−Imax_δ) and, less than theupper limit current limit (+Imax_δ), poses no restriction by the limitvalue and calculates the basic δ-axis current value (I δ0*) as theδ-axis current value (I δ*).

The torque current limiting unit 101 outputs the calculated δ-axiscurrent command value (I δ) to the output torque estimation unit 103,the torque current estimation unit 110, and the subtractor 41 and thelike.

In the rotor flux estimation unit 102, as shown in equation (7), bymultiplying the previous value (I γ_Z*) of the γ-axis current commandvalue (I γ*) calculated by the excitation current limiting unit 112 witha function including the mutual inductance M and the response timeconstant of the rotor flux (τ φ), calculates the rotor flux estimationvalue (φ est_z) for outputting to the output torque estimation unit 103.

$\begin{matrix}{\phi_{{est}\_ z} = {\frac{M}{{\tau_{\phi}s} + 1}I_{{\gamma\_}z}^{*}}} & (7)\end{matrix}$

The response time constant of the rotor flux (τ φ) is represented byLr/Rr, wherein Lr represents the self-inductance of the rotor, and Rrindicates the rotor resistance. Lr, Rr are pre-set values previously setby calculation or experiment.

The output torque estimation unit 103, as indicated by the equation (8),calculates the output torque estimate (T m_est) by multiplying the rotorflux estimate (φ est_z) with the δ-axis current value (I δ), and thetorque constant (K Te) for outputting to the torque deviationcalculating unit 105.T _(m) _(_) _(est) =K _(Te)·φ_(est) _(_) _(z) ·I* _(δ)  (8)

The torque constant (K Te) is represented by p·M/Lr, wherein prepresents the number of pole pairs, M represents a mutual inductance,and Lr indicates the self-inductance of the rotor. p, M, and Lr arepre-set values obtainable through calculation or experiment.

The ideal response torque calculating unit 104, as shown in equation(9), calculates a torque ideal response value (T m_ref) by multiplyingthe post-damping torque command value (T m2*) with a function includingtime constant (τ m) for outputting to the torque deviation calculatingunit 105.

$\begin{matrix}{T_{m\_{ref}} = {\frac{1}{{\tau_{m}s} + 1}T_{m\; 2}^{*}}} & (9)\end{matrix}$Wherein, the time constant (τ m) is a time constant that determines theideal response of the motor torque.

The output torque is a non-linear value to be represented by the productof the rotor flux and the current response values, with reference toEquation (8). However, in the present embodiment, as shown by Equation(9), the output torque (T m_ref) in the ideal response is calculated, asshown in Equation (9), to assume a value approximate to the response ofthe primary delay.

The torque deviation calculating unit 105, as shown in Equation (10),calculates a motor torque deviation (ΔT m) by calculating the differencebetween the output torque estimation unit (T m_est) and the torque idealresponse value (T m_ref) for outputting to the integration reset judgingunit 106.ΔT _(m) =T _(m) _(_) _(est) −T _(m) _(_) _(ref)  (10)

The integration reset judging unit 106, in response to the motor torquedeviation (ΔT m), determines whether or not to reset the compensationvalue of the additional compensation value calculating unit 108, andoutput to the additional compensation value calculating unit 108 a flag(flg_IRST) indicating the determination result. Conditions of judgmentand the flag are shown as follows.In case |ΔTm|≧dTm0,flag_IRST=0 (Reset inhibited)In case |dTm|<dTm0,flag_IRST=1 (Reset done)

Note that the reset determination threshold (dT m0) is a presetthreshold value to suppress the overshoot of the output torque, and setfrom the design or experiments. Further note that overshooting of theoutput torque will be described below.

When the motor torque deviation (ΔT m) is equal to the resetdetermination threshold (dT m0) or more, the integration resetdetermination unit 106 sets flag (flg_IRST) to “0” so as not to resetthe compensation value. When the motor torque deviation (ΔT m) is lessthan the reset determination threshold value (dT m0), the integrationreset determination unit 106 sets flag (flg_IRST) to “1” so as to resetthe compensation value.

The excitation current command value deviation calculating unit 107, asshown in equation (11), calculates the γ-axis current value deviation(ΔI γ*) by obtaining the difference between the magnetic fluxcompensation γ-axis current command value (I γ1*) and the previous valueof the γ-axis current command value (I γ_Z*) for outputting to theadditional compensation value calculating section 108.ΔI* _(γ) =I* _(γ1) −I* _(γ) _(_) _(z)  (11)

The additional compensation value calculating unit 108, depending on thestate of the flag (flg_IRST), as shown in equation (12) and equation(13), integrates the γ-axis current value deviation (ΔI γ*) andmultiplies with a predetermined gain to calculate a compensation value(I γ_FB) for outputting to the adder 109.

In case flag_IRST=0 (Reset inhibited),I*γ_FB=1/Tis ΔIγ*  (12)

In case flag_IRST=1 (Reset done),I*γ_FB=0  (13)

Wherein, 1/T i is an integral gain set to release a compensation valueat a predetermined response from the integrated value, representing avalue which is previously set by the design or experiments.

The adder 109, as shown in equation (14), calculates a γ-axis currentcommand value (I γ2*) before current restrictive correction by addingthe magnetic flux compensation γ-axis current command value (I γl*) tothe compensation value (I γ_FB) for outputting to the excitation currentlimiting unit 112.I* _(γ2) =I* _(γ1) +I* _(γ) _(_) _(FB)  (14)

At this time, among the command values input to the adder 109, a commandvalue that is compensated for by the flux response compensation unit 32is a magnetic flux compensation γ-axis current value (I γ1*). Asdescribed above, the compensation control of the control arrangementshown in FIG. 5 intended to be such control for increasing the responsespeed of the excitation current in accordance with the judgment resultof the compensation denervation unit 34. Therefore, the adder 109receives the excitation current command value among thepost-compensation command values of flux response compensation unit 32.On the other hand, no compensation is made for increasing the responsespeed with respect to the command value of the torque current. which ismade use of for setting a limit value of the excitation current.

The torque current estimating unit 110, as shown in equation (15),calculates a δ-axis current estimation value (I δ_est*) by multiplyingthe δ-axis current command value (I δ*) with a function that includes aresponse time constant of the stator current (τ i) for outputting to theexcitation current limit value calculating unit 111.

$\begin{matrix}{I_{{\delta\_}{est}}^{*} = {\frac{1}{{\tau_{i}s} + 1}I_{\delta}^{*}}} & (15)\end{matrix}$

The excitation current limit value calculation unit 111, as shown inequation (16), calculates a γ-axis current limit value (I γlim) based onthe maximum current limit (I max) and a δ-axis current estimated value(I δ_est*) for outputting to the excitation current limiting unit 112.I _(γlim)=√{square root over ((I _(max))²−(I* _(δ) _(_) _(est))²)}  (16)Wherein the maximum current limit (I max) is a current value indicatingthe rated current of the motor 3 and is a value determined in advance atthe design stage.

The excitation current limiting unit 112 calculates the γ axis currentcommand value (I γ*) by applying a restriction of the γ-axis currentlimit value (±I γlim) on the input γ-axis current value (I γ2*) foroutputting to the rotor flux estimation unit 102, the adder 41, etc.

The excitation current limiting unit 112 calculates the upper limitγ-axis current limit value (+I γlim) as the γ-axis current command value(I γ*), when the γ-axis current command value (I γ2*) is higher than theupper limit γ-axis current limit value (I γlim).

The torque current limiting unit 101 calculates the current limit value(−Imax_δ) as the γ-axis current command value (I γ*), when the γ-axiscurrent value (I γ2*) is less than the lower limit of the γ-axis currentlimit value (−I γlim) than the lower current limit value I is calculatedas. Also, the torque current limiting unit 101, when the γ-axis currentcommand value (I γ2*) is higher than the lower current limit of theγ-axis current command value (−I γlim), then no restriction by thelimiting values is provided and the γ-axis current command value (I γ2*)is calculated as a γ-axis current value (I γ*).

Now, with reference to FIG. 6, a description is given of a detailedconfiguration of a torque current compensation control unit 200. FIG. 6is a block diagram showing the configuration of a magnetic flux responsecompensation unit 32 and the torque current compensation control unit100.

The torque current compensation control unit 200 includes an excitationcurrent limiting unit 201, a rotor flux estimation unit 202, an outputtorque estimation unit 203, an ideal response torque calculating unit204, a torque deviation calculating unit 205, an integration resetdetermination unit 206, a torque current command value deviationcomputing unit 207, an additional compensation value calculating unit208, an adder 209, an excitation current estimation unit 210, a torquecurrent limit value calculating unit 211, and a torque current limitingunit 212.

The excitation current limiting unit 201 calculates a γ-axis currentcommand value (I γ0) by applying a restriction of a current limit(±Imax_γ) on the input basic γ-axis current command value (I γ0*). Thecurrent limit value (±Imax_γ) is defined by the upper and lower limits,and is a threshold which is previously set by the design or experiments.

The excitation current limiting unit 201 outputs the calculated γ-axiscurrent command value (I γ0) to the output torque estimation unit 203,the excitation current estimation unit 210, and the subtractor 41 andthe like.

The rotor flux estimation unit 202, similarly to the rotor fluxestimation unit 102, based on the γ-axis current command value (I γ*),calculates the rotor flux estimation value (φ est_z) for outputting tothe output torque estimation unit 203.

The output torque estimation unit 203, similarly to the output torqueestimation unit 103, calculates an output torque estimation value (Tm_est) based on the rotor flux estimation value (φ est_z) and the δ-axiscurrent command value (I δ) for outputting to the torque deviationcalculating unit 205.

The ideal response torque calculating unit 204, similarly to the idealresponse torque calculating unit 104, based on the post-damping torquecommand value (T m2*), calculates a torque ideal response value (Tm_ref) for outputting to the torque deviation calculating unit 205.

The torque deviation calculating unit 205, similarly to the torquedeviation calculating unit 105, based on the output torque estimationunit (T m_est) and the torque ideal response value (T m_ref), calculatesa motor torque deviation (ΔT m) for outputting to the integration resetdetermination unit 206.

The integration reset determination unit 206, similarly to theintegration reset determination unit 106, in response to the motortorque deviation (ΔT m), determines whether not to reset thecompensation value of the additional compensation value calculating unit208, and outputs a flag (flg_IRST) indicating the determination resultthe flag to the additional compensation calculating unit 208.

The torque current command value deviation calculating unit 207, asshown in equation (17), by pursuing the difference between the magneticflux compensation δ-axis current command value (I δ1*) and the previousvalue of the δ axis current command value (I δ_Z*), calculates a δ-axiscurrent command value deviation (ΔI δ*) for outputting to the additionalcompensation value calculating unit 208.ΔI* _(δ) =I* _(δ1) −I* _(δ) _(_) _(z)  (17)

The additional compensation value calculating unit 208, in accordancewith the state of the flag (flg_IRST), as shown in equation (18) andequation (19), integrates the δ-axis current command value deviation (ΔIδ*) and multiplies with a predetermined gain to thereby calculate acompensation value (I δ_FB) for outputting to the adder 209.

In case in which flag_IRST=0 (Reset inhibited),

$\begin{matrix}{I_{{\delta\_}{FB}}^{*} = {\frac{1}{T_{i}s}\Delta\; I_{\delta}^{*}}} & (18)\end{matrix}$In case in which flag_IRST=0 (Reset done)I* _(δ) _(_) _(FB)=0  (19)

Here, 1/T i is the preset integral gain to release a compensation valueat a predetermined response with respect to the integrated value andpreviously set by the design or experiments.

The adder 209, as shown in equation (20), by adding the magnetic fluxcompensation δ-axis current command value (I δ1*) and the compensationvalue (I δ_FB), calculates the δ-axis current command value (I δ2*)prior to a current limiting compensation for outputting to the torquecurrent limiting unit 212.I* _(δ2) =I* _(δ1) +I* _(δ) _(_) _(Fb)  (20)

At this time, among the command values which are input to the adder 209,the command value that has been compensated for by the flux responsecompensation unit 32 is a magnetic flux compensator δ-axis currentcommand value. As described above, the compensation control of thecontrol arrangement shown in FIG. 6 is intended to increase the responsespeed of the torque current in response to the determination result ofthe compensation determination unit 34. Therefore, among the commandvalues after compensation of the magnetic flux response compensationunit 32, the torque current command value is input to the adder 209. Onthe other hand, the command value of the excitation current does notundergo any compensation and is used for setting the limit value of thetorque current.

The excitation current estimation unit 210, as shown in equation (21),by multiplying the basic γ axis current command value (I γ0*) with afunction containing the response time constant of the stator current (τi), calculates a γ-axis current estimation value (I γ_est*) foroutputting to the torque current limit value calculating unit 211.

$\begin{matrix}{I_{{\gamma\_}{est}}^{*} = {\frac{1}{{\tau_{i}s} + 1}I_{\gamma}^{*}}} & (21)\end{matrix}$

Setting of the time constant (τ i) is similar to equation (15). Notethat this control process may be omitted when the γ-axis current commandvalue is constant.

The torque current limit value calculating unit 211, as shown inequation (22), based on the maximum current limit (I max) and the γ-axiscurrent estimation value (I γ_est*), calculates the δ-axis current limitvalue (I δlim) for outputting to the torque current limiting unit 212.I _(δlim)=√{square root over ((I _(max))²−(I _(γ) _(_) _(est))²)}  (22)

The torque current limiting unit 212, by applying restriction of theδ-axis current limit value (±I δlim) to the input δ-axis current commandvalue (I δ2*), calculates the δ-axis current command value (I δ *) foroutputting to the rotor flux estimation unit 202 and the subtractor 41and the other operation unit.

Now, among the control of the compensation control unit 35, adescription is give of the control of the excitation currentcompensation control unit 100 with reference to FIG. 5.

When the compensation determination unit 34 determines that the amountof change in the basic γ-axis current command value (dI γ0*) is largerthan the determination threshold value (I 0) and the change of theexcitation current is determined to be large, the excitation currentcommand value is compensated for by amplifying the excitation currentcommand value such that the phase of the excitation current commandvalue will be advance to increase the response speed of the excitationcurrent.

Assuming (and unlike the present embodiment) that, with respect to theamplified excitation current command value, the excitation current isallowed to flow to the maximum current limit value, a large excitingcurrent would flow transiently due to the advance compensation. However,from the viewpoint of protection against over-current to the motor, itis impossible to flow in the motor a current exceeding the maximumcurrent limit value. If the excitation current would be allowed to flowto the maximum current limit, all the current will flow to the excitingcurrent, and it is impossible to flow a torque current. As a result, itis not possible to generate a torque. Rather, the torque response isdelayed.

Therefore, in the present embodiment, the excitation currentcompensation control unit 100, based on the basic δ-axis current commandvalue (I δ0*), estimates a torque current (equivalent to the δ-axiscurrent estimation value (I δ_est*)) and, based on the estimated torquecurrent value, calculates the γ-axis current limit value (I γlim). Thiscontrol corresponds to the control by the torque current estimation unit110 and the excitation current limit value calculating unit 111 in thecontrol block in FIG. 5.

Thus, in the present embodiment, in order for the torque current not tobecome zero, since it is possible to add restrictions to the amplifiedexcitation current command value, the output torque can be preventedfrom being zero, which would lead to occurrence of a dead time.

The γ-axis current command value (I γ2*) which has been amplified by theflux response compensation unit 32 is subject to restriction by theexcitation current limiting unit 112. Out of the amplified γ-axiscurrent command value of the (I γ2*), a part of the command value whichis restricted by the γ-axis current limit value (I γlim) is not used forcompensation of the excitation current. On the other hand, by control ofthe motor 3 at the excitation current command value in excess of theγ-axis current limit value (I γlim), as described above, there is apossibility that the torque current becomes zero.

Therefore, the excitation current compensation control unit 100calculates a compensation value based on the portion of the commandvalue of the amplified γ-axis current value (I γ2*), which has beenrestricted by the γ-axis current limit value (I γlim), and, by applyinga feedback, adds to the γ-axis current command value (I γ1*). Inaddition, the excitation current compensation control unit 100calculates the compensation value to be added by integrating thedifference between γ-axis current command value (I γ1*) and γ-axiscurrent limit value (I γlim), added by integrating We have calculatedthe compensation value.

Even when such a state in which the amplified γ-axis current commandvalue (I γ1*) exceeds the γ-axis current limit value (I γlim) iscontinued, the command value corresponding to the portion exceeding theγ-axis current limit value (I γlim) will be accumulated by integration.Then, when the γ-axis current command value (I γ1*) falls below theγ-axis current limit value (I γlim), the compensation value accumulatedwill be added to the γ-axis current command value limit value (I γ1*),which is lower than the γ-axis current limit value (I γlim). Thiscontrol corresponds to the controls by the excitation current commandvalue deviation calculating unit 107, the additional compensation valuecalculating unit 108, the adder 109, and the excitation current limitingunit 112 in the control block in FIG. 5.

Thus, after the γ axis current command value (I γ1*) has fallen belowthe γ-axis current limit value (I γlim) (i.e., the current limit hasbeen released with respect to the γ-axis current value (I γ1*)), it ispossible to allow the portion of the excitation current command value,which has not been able to be compensated for due to the currentrestriction. Further, a sufficient excitation current is retained afterrestriction release of the γ-axis current value (I γ1*) so that a largeexcitation current may be maintained. As a result, it is possible toincrease the torque response.

Further, the excitation current compensation control unit 100 calculatesa difference between the output torque of the motor 3 and the torquecommand value by calculating a difference between the output torqueestimate (T m_est) and the torque ideal response value (T m_ref), and,based on the difference, sets the timing for resetting the compensationvalue. Note that the output torque estimate (T m_est) corresponds to theoutput torque, and the torque ideal response value (T m_ref) correspondsto the torque command value. This control corresponds to the rotor fluxestimation unit 102, the output torque estimation unit 103, the idealresponse torque calculating unit 104, the torque deviation calculatingunit 105 and the integration reset determination unit 106 of the controlblock in FIG. 5.

Here, unlike the present embodiment, among the above conditions of theintegration reset determination unit 106, a description is given of acase in which, despite the condition |ΔT m|<dT m0 being satisfied,resetting of the compensation value is not made.

When the output torque estimate value (T m_est) is small compared to thetorque ideal response value (T m_ref) and thus the motor torquedeviation (ΔT m) is less than the reset determination threshold value(dT m0), if the additional compensation would be continued withoutresetting the compensation value by the additional compensation valuecalculating unit 108, the excitation current will continue to rise bythe additional compensation although the motor 3 is outputting a torqueclose to the torque ideal response value (Tm_ref). In this instance,when the high torque is continuously output, by the additionalcompensation, the output torque will exceed a target torque, which willlikely to generate overshooting of the output torque.

Therefore, in the present embodiment, the excitation currentcompensation control unit 100, in order to prevent this overshoot, setsthe reset determination threshold (dT m0). When the motor torquedeviation (ΔT m) is less than the reset determination threshold, thecompensation value is controlled to be reset.

Thus, in the present embodiment, since the compensation value isconfigured to be converged to zero after the difference between thetorque command value and the output torque has reduced, the excitationcurrent command value subject to the additional compensation may bedecreased to the command value which is compensated for by the fluxresponse compensation unit 32.

Consequently, without causing an overshoot of the actual torque, it ispossible to match the actual torque to the torque command value.

Now, among the control of the compensation control unit 35, adescription is given of the control of the torque current compensationcontrol unit 200 with reference to FIG. 6. The control of the torquecurrent of the torque current compensation control unit 200 is similarto the control of the excitation current of the excitation currentcompensation control unit 100. Also, the control of the excitationcurrent of the torque current compensation control unit 200 is similarto control of the torque current of the excitation current compensationcontrol unit 100.

The torque current compensation control unit 200, based on the basic γaxis current command value (I γ0*), estimates the torque current(equivalent to the γ-axis current estimated value (I γ_est*)), and,based on the estimated torque current value, calculates the δ-axiscurrent limit value (I δlim). This control corresponds to the control ofthe excitation current estimation unit 210 and the excitation currentlimit value calculating unit 211 of the control block in FIG. 6.

Also, the torque current compensation control unit 200 calculates acompensation value based on the portion of the command value of theamplified δ-axis current value (I δ2*), which has been restricted by theδ-axis current limit value (I δlim), and, by applying a feedback, addsto the δ-axis current command value (I δ1*). In addition, the torquecurrent compensation control unit 200 calculates the compensation valueto be added by integrating the difference between δ-axis current commandvalue (I δ1*) and δ-axis current limit value (I δlim).

This control corresponds to a torque current command value deviationcalculating unit 207, the additional compensation value calculating unit208, the adder 209, and the torque current limiting unit 212 of thecontrol block in FIG. 6.

Further, the torque current compensation control unit 200 calculates adifference between the output torque of the motor 3 and the torquecommand value by calculating a difference between the output torqueestimate (T m_est) and the torque ideal response value (T m_ref), and,based on the difference, sets the timing for resetting the compensationvalue. This control corresponds to the rotor flux estimation unit 202,the output torque estimation unit 203, the ideal response torquecalculating unit 204, the torque deviation calculating unit 205 and theintegration reset determination unit 206 of the control block in FIG. 6.

Now, with reference to FIG. 7, a description will be given of controlprocedure of the motor controller 20. FIG. 7 is a flow chart showing acontrol procedure of the motor controller 20. Note that the control flowof FIG. 7 is executed repeatedly at a predetermined cycle.

In step S1, the motor controller 20 acquires, as the input process, avehicle speed, an accelerator opening and the like. In step S2, themotor torque control unit 21, based on the input accelerator opening,etc., calculates a torque command value (T m1*). In step S3, the dampingcontrol unit 22, by performing the vibration suppression control basedon the torque command value (T m1*), etc., calculates a post-dampingcontrol torque command value (T m2*).

In step S4, the current command value calculating unit 30 in the currentcontrol unit 23, based on the post-damping control torque command value(T m2*), etc., calculates γδ-axis current command values (I γ *, I δ *).Note that the detailed control procedure of step S4 will be describedbelow.

Subsequently, in step S5, the subtractor 41 and the like included in thecurrent controller 23 generates a drive signal (switching signal) so asto output the γδ-axis current command values (I γ *, I δ*) from themotor 3 for outputting to the inverter 2 to thereby control the inverter2.

Now, with reference to FIG. 8, a description will be given of a controlprocedure of step S4. FIG. 8 is a flow chart showing a control procedureof step S4.

Subsequent to the control in step S3, in step S41, the basic currentcommand value calculating unit 31, based on the post-damping controltorque command value (T m2*), etc., calculates basic γδ-axis currentcommand values (I γ0*, I δ0*). In step S42, the magnetic flux responsecompensation unit 32, by amplifying the basic γ axis current commandvalues (I γ0*, I δ0*), compensates for the delay of the rotor fluxresponse of the drive motor 3 and calculates magnetic flux compensationγδ axis current command values (I γ1*, I δ1*).

In step S43, the excitation current command value change amountcalculating unit 33, based on the magnetic flux compensation γ-axiscurrent command value, based on (I γ1*), calculates the amount of changein the γ-axis current command value (dI γ0*). In step S44, thecompensation determination unit 34 compares the amount of change of theγ-axis current value (dI γ0*) and a determination threshold value (I 0).

When the amount of change in the γ-axis current command value (dI γ0*)is greater than the determination threshold value (I 0), thecompensation control unit 35 performs a control such that the excitationcurrent is additionally compensated for by the excitation current (stepS45). On the other hand, when the amount of change in the γ-axis currentvalue (dI γ0*) is equal to or less than the determination threshold (I0), the compensation control unit 35 is configured to control toadditionally compensate for the torque current by the torque currentcompensation control unit 100 (step S46). Subsequently, followingcompletion of the additional compensation control in steps S45, S46,after completion of the control flow of step S4, control proceeds tostep S5.

Now, with reference to FIG. 9, a description is given of the controlprocedure of step S45. FIG. 9 is a flow chart showing a controlprocedure of step S45.

In the control in step S45, first in step S451, the torque currentlimiting unit 101 applies to the basic δ-axis current command value (Iδ0*) a restriction of current limit (±Imax_δ) to thereby calculate aδ-axis current command value (I δ*).

The torque current estimation unit 110, on the basis of the δ-axiscurrent command value (I δ*), estimates the δ-axis current estimatedvalue (I δ_est*). In addition, the excitation current limit valuecalculating unit 111, based on the δ-axis current estimated value (Iδ_est*), calculates the basic γ-axis current limit value (I γlim) (stepS452).

In step S453, the ideal response torque calculating unit 104, based onthe post-damping control torque command value (T m2*), calculates thetorque ideal response value (T m_ref).

The rotor flux estimation unit 102, based on the previous value (I γ_Z*)of the γ-axis current command value (I γ *), calculates the rotor fluxestimation value (φ est_z). Moreover, the output torque estimation unit103, based on the rotor flux estimate (φ est_z), calculates the outputtorque estimation value (T m_est) (step S454).

In step S455, the torque deviation calculating unit 105, by calculatinga difference between the torque ideal response value (T m_ref) and theoutput torque estimated value (T m_est), calculates a motor torquedeviation (ΔT m). In step S456, the integration reset determination unit106 compares the motor torque deviation (ΔT m) and the resetdetermination threshold (dT m0).

When the motor torque deviation (ΔT m) is the reset determinationthreshold (dT m0) or above, the integration reset determination unit 106sets the flag (flg_IRST) to “0 (reset inhibited or disabled)” (stepS457). When the motor torque deviation (ΔT m) is less than the resetdetermination threshold value (dT m0), the integration resetdetermination unit 106 sets the flag (flg_IRST) to “1 (reset done orimplemented)” (step S458).

In step S459, the excitation current command value deviation calculatingunit 107, by calculating the difference between the magnetic fluxcompensation γ-axis current command value (I γ1*) and the previous value(I γ_Z*) of the γ-axis current command value, calculates the γ-axiscurrent command value deviation (ΔI γ *). In step S460, the additionalcompensation value calculating unit 108 calculates the integrated valueby integrating the γ-axis current command value deviation (ΔI γ *). Instep S461, the additional compensation value calculating unit 108, bymultiplying a predetermined gain with the integrated value, calculatesthe compensation values (I γ_FB).

In step S462, the additional compensation value calculating unit 108determines whether or not the flag (flg_IRST) is “1”. When the flag(flg_IRST) is “1”, at step S463, the additional compensation valuecalculating unit 108, by setting the compensation value (I γ_FB) tozero, resets the compensation value (I γ_FB). On the other hand, whenthe flag (flg_IRST) is “1”, the compensation value (I γ_FB) will not bereset and control proceeds to step S464.

In step S464, the adder 109, by adding the flux compensation γ-axiscurrent command value (I γ1*) and the compensation value (I γ_FB),calculates the γ-axis current value (I γ2*) prior to the currentlimiting compensation.

In step S465, the excitation current limiting unit 112, in order to puta restriction on the γ-axis current command value (I γ2*) prior to thecurrent limiting compensation by the γ-axis current limit value (Iγlim), compares the relative magnitude between the γ-axis currentcommand value (I γ2*) and the γ-axis current limit value (I γlim).

When the γ axis current command value (I γ2*) is within the rangebetween the negative side limit value (−I γlim) and the positive sidelimit value (+I γlim), the excitation current limiting unit 112, withoutposing a restriction on the command value, outputs the γ axis currentcommand value (I γ2*) as the γ-axis current value (I γ *) (step S466).On the other hand, when the γ-axis current command value (I γ2*) isoutside the range between the negative-side limit value (−I γlim) andthe positive limiting value (+I γlim), the excitation current limitingunit 112, by applying a limit to the command value, output the γ-axiscurrent limit value (−I γlim or I γlim) as the γ-axis current commandvalue (I γ *) (step S466). Then, after completing steps S466, S467,through control flow of the step S4, control proceeds to step S5.

After step S467, in step S459 of the control flow in the nextcalculation cycle, the previous value of the γ-axis current commandvalue (I γ_Z*) will be the γ-axis current limit value (I γlim). Inaddition, the difference between the magnetic flux compensation γ-axiscurrent command value (I γl*) and the γ-axis current limit value (Iγlim) represents a portion of the γ-axis current limit value (I γlim)which has been subject to restriction by the γ-axis current limit value(I γlim). Furthermore, by integrating the difference in the control ofstep S460, it is possible to accumulate the partial command value thatcould not be reflected in the compensation for the excitation current.

Also, following step S467, in the next calculation cycle of the controlflow, when the flux compensation γ-axis current command value (I γ1*) isless than the γ-axis current limit value (I γlim), then in step S464 inthe subsequent control flow, the compensation value will be added to theexcitation current command value (I γ1*) which is less than the γ-axiscurrent limit value (I γlim).

Note that, since the control flow of step S46 is substantially similarto the control flow in which, in steps S451 to S467 shown in FIG. 9, thecontrol pertaining to the excitation current and the control pertainingto the torque current are interchanged, a description thereof will beomitted.

Now, a description is given of the effect of the motor control devicepertaining to the present invention with reference to FIGS. 10A-D andFIGS. 11A-D. FIGS. 10A-D are characteristic of a comparative example,while FIGS. 11A-D show a characteristic of the present invention. InFIGS. 10A-D, FIGS. 11A-D, FIGS. 10A, 11A show the time characteristicsof the excitation current (γ-axis current); FIGS. 10B, 11B show the timecharacteristic of the torque current (δ-axis current); FIGS. 10C, 11Cshow the time characteristic of the rotor flux; and FIGS. 10D, 11D aregraphs showing time characteristics of the torque. Also, in FIGS. 10,11, an actual torque, an actual γ-axis current, and an actual δ-axiscurrent respectively indicate the output torque of an actual motor 3 andcurrent actually flowing through the motor 3.

In the comparative example, similarly to the magnetic flux responsecompensation unit 32, by amplifying the γ-axis current command value, aphase compensation is performed to improve the rotor flux response. Inaddition, a restriction is posed by the maximum current limit on theexcitation current command value which has been compensated for by thisphase compensation.

Below, while comparing FIGS. 10A-D and 11A-D, in an operational examplein which a torque command value is increased stepwise such as in avehicle starting acceleration and the like from a stopping state, adescription will be given of the torque response performance.

At time t1, as the vehicle starting acceleration from stopping state,the torque command value rises stepwise, and the basic γδ-axis currentcommand value also rise in a stepwise manner. By the magnetic fluxresponse compensation unit 32, through the phase compensation to improvethe rotor flux response, the flux compensation γ-axis current commandvalue exhibits a transient large value.

In Comparative Example, with the maximum current limit value being setas the upper limit value of the current amplitude, the excitationcurrent is amplified so as to distribute current to the γ-axis currentas compared to the δ-axis current. Thus, in the Comparative Example,since the current is used up only for γ-axis current value up to themaximum current limit, the current value that can be used for the δ-axiscurrent remained remains zero. Therefore, a dead time (corresponding toΔt n in FIGS. 10A-D) is generated in which no torque can be produced.Moreover, since the γ-axis current is limited by the rated current limitvalue (equivalent to a maximum current limit), a desired current toimprove the rotor flux response will not flow so that desired rotorsflux responses cannot be realized.

Then, at a time between the time t1 and t2, when the magnetic fluxcompensator γ-axis current command value decreases and falls below thevalue of the maximum current limit value, it is possible to flow aδ-axis current so that torque starts rising.

At time t2, although the rotor flux rises up to 70 to 80 percent of thesteady-state value, the magnetic flux compensation γ-axis currentcommand value converges almost to the basic γ-axis current commandvalue. At time t2 and thereafter, the γ-axis current is maintained atabout constant value, and, with a delay of a time constant determined bythe characteristics of the rotor, the rotor flux gradually rises.Consequently, due to the slow response speed or a slow torque response,it takes until time t5 to t6 for the time to converge to a final torquecommand value of the actual torque.

In the present invention, at time t1, torque command value risesstepwise, and the basic γδ-axis current command value also risestepwise. With respect to the δ-axis current, according to the presentinvention, while applying a limit of the maximum current limit(corresponding to a current limit value (±Imax_δ)) to the δ axis currentcommand value, the δ-axis current is allowed to flow. Therefore, in theperiod in which a dead time has been caused in the Comparative Example,according to the present invention, the δ-axis current command valuewill not be made zero so that it is possible to launch the δ-axiscurrent quickly. As a result, the torque also rises from the time t1without waste time.

As for γ-axis current, due to the phase compensation by the magneticflux response compensation unit 32 to improve the rotor flux response,the flux compensation γ-axis current command value rises transiently toa large value. Further, the limit applied to the magnetic fluxcompensation γ-axis current command value is a portion obtained bysubtracting the δ-axis current command value from the maximum currentlimit value so as to set the maximum current limit value to the currentamplitude, and the γ-axis current limit value (equivalent to currentlimit value (±I γlim)) is determined.

Therefore, in accordance with the rise of the δ-axis current commandvalue, the γ-axis current value is limited and depressed.

Thus, although the torque response immediately after the time t1 isfaster without a dead time compared to the Comparative Example, duringthe period from time t1 to t2, the rising amount of the actual torque istemporarily smaller than that of the Comparative Example. However, atthe time t2, the magnitude of the actual torque is substantially thesame order.

Further, in the period between time t1 and t2, while the magnetic fluxcompensation γ-axis current command value exceeds the current limitvalue of the excitation current, by accumulating and integrating thedifference between the magnetic flux compensation γ-axis current commandvalue and the current limit value, the command value will be compensatedfor and γ-axis current command value which will be input to theadditional compensation γ-axis current command value (corresponding tothe γ-axis current command value (I γ2*) input to the excitation currentlimiting unit 112) will be increased gradually. When the magnetic fluxcompensation γ-axis current command value decreases and falls below theγ-axis current limit value, the additional compensating γ-axis currentvalue may be maintained at a value greater than the magnetic fluxcompensator γ-axis current value by the integral value that has beenaccumulated. Then, after the current limit release, a portion of theflux compensation γ-axis current command value that could not beeffective due to the current limit may be applied at the timing ofrelease of the current limit.

Thus, at the time t2 and thereafter, a longer convergence time to reachthe command value is required in the Comparative Example due to thedeterioration in torque response. In contrast, according to the presentinvention, the torque may be continuously increased so that the targetcommand value has been achieved before time t3.

Furthermore, in the present invention, the output torque substantiallymatches the torque command value immediately before time t3, it isdetected that the change amount of the output torque is reduced and, byconverging the integrated value of the compensation value to zero, theadditional compensation γ-axis current command value is reduced to themagnetic flux compensation γ-axis current command value. Therefore,according to the present invention, without causing an overshoot of theactual torque, the actual torque can be matched to the torque commandvalue.

As described above, in the present embodiment, the basic γδ-axis currentcommand values (I γ0*, I δ0*) are amplified to compensate for the delayin the rotor flux response to calculate the flux compensation γδ-axiscurrent command values (I γ1*, I δ1*). The γδ-axis current commandvalues (I γ2*, I δ2*) are restricted by the γδ-axis current limit values(I γlim, I δlim). Compensation values (I γ_FB, I δ_FB) are calculatedbased on the flux compensation γδ-axis current command values (I γ1*, Iδ1*) and the γδ-axis current command value (I γ *, I δ *) restricted bythe γδ-axis current limit values (I γlim, I δlim). The flux compensationγδ-axis current command values (I γ1*, I δ1*) and the compensationvalues (I γ_FB, I δ_FB) are added to calculate the γδ-axis currentcommand values (I γ2*, I δ2*). A portion of the command value of theflux compensation γδ-axis current command values (I γ1*, I δ1*), whichhas been subject to restriction or limitation by the γδ-axis currentlimit values (I γlim, I δlim) is calculated as the compensation values(I γ_FB, I δ_FB). Thus, when the magnetic flux compensator γ-axiscurrent command values (I γ1*, I δ1*) are restricted by the limit value,a portion of the magnetic flux compensator γδ-axis current commandvalues (I γ1*, I δ1*) may be added for additional compensation upon themagnetic flux compensator γδ-axis current command values (I γ1*, I δ1*)falling below the limit value. Therefore, the torque responsiveness maybe improved.

Also, in the present embodiment, by integrating the difference betweenthe magnetic flux compensation γδ-axis current command value (I γ1*, Iδ1*) and the γδ-axis current limit value (I γlim, I δlim), thecompensation value (I γ_FB, I δ_FB) is calculated. Thus, since a portionof the magnetic flux compensation γδ-axis current command value thatcould not be output by the current limit (I γ1*, I δ1*) is accumulated,when the flux compensation γδ-axis current command value (I γ1*, I δ1*)becomes smaller than the limit value, it is possible to output theaccumulated integrated value as the compensation value. Moreover, evenafter the current limit is released, since it is possible to maintainthe excitation current in a high state, against abrupt change of thetorque command value, it is possible for the actual torque to convergequickly to the command value.

Also, in the present embodiment, a predetermined gain (1/Ti) ismultiplied with the integrated value which integrates the differencebetween the magnetic flux compensation γδ-axis current command value (Iγ1*, I δ1*) and the γδ-axis current limit value (I γlim, I δlim) tocalculate the compensation value (I γ_FB, δ_FB). This makes it possibleto output the accumulated integration value with a desired response.

Also, in the present embodiment, the compensation value (I γ_FB, I δ_FB)I is suppressed by adjusting the gain (1/T i) such that the γδ-axiscurrent command value (I γ2*, I δ2*) after releasing the current limitis not transiently high, by adjusting. That is, in the presentembodiment, after the current limitation is released, the accumulatedvalue is released to the integrated value to be added to the magneticflux compensation γδ-axis current command value (I γ1*, I δ1*). Further,by the time constant of the rotor flux, the actual rotor flux riseslater with a delay than forecast from the magnetic flux compensationγδ-axis current command value (I γ1*, I δ1*). Until the current limit isreleased, the rotor flux is has risen somewhat, with the rotor fluxrise, the compensation value of the integrated value will be added tothe magnetic flux compensation γδ-axis current command value (I γ1*, Iδ1*). Therefore, without gain adjustment, if an integrated value isdischarged as it is and added to the magnetic flux compensation γδ-axiscurrent command value (I γ1*, I δ1*), the rotor flux will be launchedtransiently steeper than necessary so that there is a risk of overshootof the output torque. Therefore, in the present embodiment, theintegrated value is subjected to gain adjustment to prevent overshoot ofthe output torque so that the steady-state value is controlled accordingto the command value and the responsiveness is improved in the transientresponsiveness only.

Further, in the present embodiment, based on the difference between thepost-damping control torque command value (T m2*) and the output torque,the compensation value (I γ_FB, I δ_FB) will be reset. This makes itpossible to avoid transient overshoot of the rotor flux and torque.

Also, in the present embodiment, based on the basic γδ-axis currentcommand value (I γ0*, I δ0*) which is not compensated for by themagnetic flux response compensation unit 32, the current value of thosewhich are not compensated is estimated. Further, based on the estimatedcurrent value (I γ_est*, I δ_est*), the γδ-axis current limit value (Iγlim, I δlim) is calculated. Thus, since a limit value of the currentcommand value to be additionally compensated is provided, occurring ofdead time as describe above in the Comparative Example will be preventedto occur, for example.

Also, in the present embodiment, based on the current command valuewhich is not compensated by the magnetic flux response compensation unit32 and the maximum current limit (I max), the γδ-axis current limitvalue (I γlim, I δlim) is calculated. However, among the current commandvalue, the maximum current limit (Imax) and the (I γlim, I δlim),equation (16) or equation (22) is satisfied. Note that equations (16)and (22) includes the γδ-axis current estimated value (I γ_est*, Iδ_est*). However, in place of the estimated value, the basic γδ-axiscurrent command value (I γ0*, I δ0*) may be used.

Thus, the current command value which does not subject to compensationfor the high response processing is reliably allowed to flow. Thus, thedead time due to the arrangement in which current will not be able toflow in one of the γδ axes may be eliminated to thereby produce thetorque reliably.

Also, in the present embodiment, by amplifying the basic γδ-axis currentcommand value (I γ0*, I δ0*) to compensate for the delay of the rotorflux response of the motor 3 to thereby calculate a flux compensationγδ-axis current command value (I γ1*, I δ1*) (first compensation) Themagnetic flux compensation γδ-axis current command value (I γ1*, I δ1*)is further compensated for to calculate a γδ-axis current command value(I γ2*, I δ2*) (second compensation). The γδ-axis current command value(I γ2*, I δ2*) is restricted by the γδ-axis current limit value (I γlim,I δlim). When restricting by the γδ-axis current limit value (I γlim, Iδlim), depending on the magnitude of the flux compensation γδ-axiscurrent command value (I γ1*, the restriction is made. In the secondcompensation, after the magnetic flux compensation γδ-axis currentcommand value (I γ1*, I δ1*) falls below the γδ-axis current limit value(I γlim, I δlim), a portion of the command value which has been subjectto restriction by the γδ-axis current limit value (I γlim, I δlim) isadded to the magnetic flux compensation γδ-axis current command value (Iγ1*, I δ1*). Thus, when the magnetic flux compensation γδ-axis currentcommand value (I γ1*, I δ1*) is partly restricted by the limit value,the portion of the flux compensation γδ-axis current command value (Iγ1*, I δ1*) that cannot be output due to the current limit is added whenthe magnetic flux compensation γδ-axis current command value (I γ1*, Iδ1*) becomes smaller than the limit value. Thus, the compensation may beadditionally made to increase the torque response.

Note that, in the present embodiment, when calculating the slip angularvelocity ωse, the slop angular velocity calculating unit 49 may use theprevious value I γ_z, I δ_z of the current measurement value, instead ofusing the current command value I γ*, the I δ*.

Note that, in the present embodiment, when calculating the torque idealresponse value (T m_ref), the ideal response torque calculating unit 104may use the post-damping control torque command value (T m2*) as thecommand value, which has been calculated in the previous calculationtiming. As described above, the rotor magnetic flux estimation unit 102uses the γ-axis current command value (I γ_Z*) obtained in the previouscalculation timing. Thus, in the ideal response torque calculating unit104 as well, by using the post-damping control torque command value(Tm2*) for calculating the torque ideal response value (Tm_ref) forphase match.

Note that, the additional compensating value calculating unit 108 may beconfigured, when resetting the compensation value in response to theflag set by the integration reset determination unit 106 changing from“0” to “1” to cause the compensation value to be converged to zero withthe passage of a predetermined time period from when the flag is changedfrom “0” and “1”.

Note that the torque current estimation unit 110, in view of the delaydue to control operation, may use the previous value of the basic δ-axiscurrent command value instead of the basic δ-axis current command value(I δ0*). Alternatively, the torque current estimation unit 110 may usethe actually detected value of the torque current detected by thesensor.

The basic current command value calculating unit 31 described abovecorresponds to the “current command value calculating means or device”of the present invention; the magnetic flux response compensation unit32 corresponds to the “first compensation means or device” of theinvention; the excitation current limiting unit 112 or the torquecurrent limiting unit 212 correspond to the “first current command valuelimiting means or device” of the present invention; the excitationcurrent command value deviation calculating unit 107, the torque currentcommand value deviation calculation unit 207, and the additionalcompensation value calculating units 108 and 208 corresponds to the“second compensation means or device” of the present invention, theadders 109, 209 correspond to the“adding means or device”; and theexcitation current limit value calculating unit 111 and the torquecurrent limit value calculating unit 211 correspond to the “firstcurrent limit value calculating means or device” of the presentinvention, respectively.

Second Embodiment

FIG. 12 shows a block diagram of the excitation current compensationcontrol unit 100 of the motor control device pertaining to anotherembodiment according to the present invention. FIG. 13 is a blockdiagram of a torque current compensation control unit 200 of the motorcontrol device. In the present embodiment, compared to the firstembodiment described above, The first embodiment described above in thisexample, part of the configuration of the excitation currentcompensation control unit 100, and, part of the structure of the torquecurrent compensation control unit 200 are different. Other than theseconfigurations are the same as the first embodiment, the descriptionthereof is appropriately incorporated.

As shown in FIG. 12, the excitation current compensation control unit100 includes a torque current limiting unit 101, an integration resetdetermination unit 106, an excitation current command value deviationcalculating unit 107, an additional compensation value calculating unit108, an adder 109, a torque current estimation unit 110, an excitationcurrent limit value calculating unit 111, an excitation current limitingunit 112, and an excitation current deviation calculating unit 113.

The excitation current deviation calculating unit 113, as shown inequation (23), by calculating the difference between the basic γ axiscurrent command value (I γ0*) and a magnetic flux compensation γ-axiscurrent command value (I γ1*), calculates the deviation of theexcitation current command value (ΔI γ10*) for outputting to theintegration reset judgment unit 106.ΔI* _(γ10) =I* _(γ1) I* _(γ0)  (23)

The integration reset judging unit 106, in response to the excitationcurrent command value deviation (ΔIγ10*), determines whether or not toreset the compensation value of the additional compensation valuecalculating unit 108, and outputs to the additional compensation valuecalculating unit 108 a flag (flg_IRST) indicating the determinationresult. Conditions of the judgment and the flag are shown as follows.In case |ΔIγ10*|≧dIγ10*,flag_IRST=0 (Reset inhibited)In case |ΔIγ10*|<dIγ10*,flag_IRST=1 (Reset done)Note that the reset determination threshold (dIγ10* is a presetthreshold value to suppress the overshoot of the output torque, and setfrom the design or experiments.

The additional compensation value calculating unit 108, based on thedifference between the basic γ axis current command value (I γ0*) andthe magnetic flux compensation γ-axis current command value (I γ1),resets the compensation value (I γ_FB). The difference between the basicγ axis current command value (I γ0*) and the magnetic flux compensationγ-axis current command value (I γ1) corresponds to the amount or portionof the command value that has been amplified by the rotor flux responsecompensation of the flux response compensation unit 32.

Therefore, in the period where the amount of the command value which wasamplified in the magnetic flux response compensation unit 32 is equal toor greater than the reset determination threshold, the additionalcompensation value calculating unit 108 and the adder 109 perform theadditional compensation of the excitation current. When the amount ofthe command value amplified by the magnetic flux response compensationunit 32 falls below the reset determination threshold, the compensationvalue is reset by the additional compensation value calculating unit108. The additional compensation of the excitation current is therebycompleted.

As shown in FIG. 13, the torque current compensation control unit 200includes an excitation current limiting unit 201, an integration resetdetermination unit 206, a torque current command value deviationcalculating unit 207, an additional compensation value calculating unit208, an adder 209, an excitation current estimation unit 210, a torquecurrent limit value calculating unit 211, a torque current limiting unit212, and a torque current deviation calculating unit 213.

The torque current deviation calculating unit 213, as shown in equation(24), by calculating the difference between the basic δ-axis currentvalue (I δ0*) and the magnetic flux compensation δ-axis current value (Iδ1*), calculates a deviation of the torque current command value (ΔIδ10*) for outputting to the integration reset judgment unit 106.ΔI* _(δ10) =I* _(δ1) −I* _(δ0)  (24)

The integration reset judging unit 206, in response to the deviation ofthe torque current command value (ΔI δ10*), determines whether or not toreset the compensation value of the additional compensation valuecalculating unit 208, and outputs to the additional compensation valuecalculating unit 208 a flag (flg_IRST) indicating the determinationresult. Conditions of the judgment and the flag are shown as follows.In case |ΔIδ10*|≧dIδ10*,flag_IRST=0 (Reset inhibited)In case |ΔIδ10*|<dIδ10*,flag_IRST=1 (Reset done)Note that the reset determination threshold (dIδ10* is a presetthreshold value to suppress the overshoot of the output torque, and setfrom the design or experiments.

As described above, in the present embodiment, based on differencebetween the basic γδ-axis current command value (I γ0*, I δ0*) and theflux compensation γδ-axis current command value (I γ1*, I δ1*), thecompensation value (I γ_FB, I δ_FB) is configured to be reset. As aresult, in a period where the increased amount of the current commandvalue by the flux response compensation unit 32 is higher than apredetermined value (reset determination threshold (dI γ10*, dI δ10*)),a control is performed in which an additional compensation is applied,whereas in a period where the increased amount in the current commandvalue is lower than the predetermined value, no additional compensationis done. Consequently, it is possible to suppress the overshoot of theoutput torque while increasing the torque response.

Third Embodiment

FIG. 14 shows a block diagram of the excitation current compensationcontrol unit 100 of the motor control device pertaining to yet anotherembodiment of the invention. FIG. 15 is a block diagram of a torquecurrent compensation control unit 200 of the motor control device. Inthe present embodiment, compared to the first embodiment describe above,the configuration of the excitation current compensation control unit100 and the configuration of the torque current compensation controlunit 200 are partly different. The other configurations are the same asthe first embodiment described above. The description of the first andsecond embodiments is therefore incorporated appropriately.

As shown in FIG. 14, the excitation current compensation control unit100 includes a torque current limiting unit 101, a rotor flux estimationunit 102, an excitation current command value deviation calculating unit107, and additional compensation value calculating unit 108, an adder109, a torque current estimation unit 110, an excitation current limitvalue calculating unit 111, an excitation current limiting unit 112, atorque current limit value calculating unit 114, and a torque currentlimiting unit 115.

The torque current limit value calculating unit 114, as shown inequation (25), by dividing the post-damping control torque command value(T m2*) by a multiplied value of the torque constant (K Te) and therotor flux estimate (φ est), calculates the δ-axis current limit value(I δlim) for outputting to the torque current limiting unit 115.

$\begin{matrix}{I_{\delta\;\lim} = \frac{T_{m\; 2}^{*}}{K_{Te} \cdot \phi_{est}}} & (25)\end{matrix}$

The torque current limiting unit 115, by restricting the torque currentcommand value calculated by the torque current limiting unit 101 by thepositive and negative δ-axis current limit value (±I Slim), calculatesthe δ-axis current command value (I δ). The torque current compensationcontrol unit 200 calculates a limit value for the γ-axis current valuebased on the δ-axis current value that is not compensated for by theflux response compensation unit 32, and applies an additionalcompensation to the γ-axis current command value, which is compensatedfor by the flux response compensation unit 32 for the command value toadd restriction by the limit value of the γ-axis current. Further, basedon the γ axis current command value subject to restriction by the γ-axiscurrent limit value, a limit value for the δ-axis current value will becalculated to add restriction on the δ-axis current value. Thus, throughthe compensation by the flux response compensation unit 32 and thecompensation by the excitation current compensation control unit 100,whatever value the current command value might assume, it is possiblefor the output torque to approach the ideal response of the torquecommand value.

As shown in FIG. 15, the torque current compensation control unit 200includes an excitation current limiting unit 201, a rotor fluxestimation unit 202, an output torque estimation unit 203, an idealresponse torque calculating unit 204, a torque deviation calculatingunit 205, an integration reset determination unit 206, a torque currentcommand value deviation calculating unit 207, an additional compensationvalue calculating unit 208, an adder 209, an excitation currentestimation unit 210, a torque current limit value calculating unit 211,a torque current limiting unit 212, an excitation current limit valuecalculating unit 214, a limit value compensation unit 215, and anexcitation current limiting unit 216.

The excitation current limit value calculating unit 214, as shown inequation (26), by dividing the post-damping control torque command value(T m2*) by a multiplication value of the motor torque constant (K 1) andthe δ-axis current command value (I δ *), calculates a γ-axis currentlimit value (I γlim′) for outputting to the limit value correcting unit215.

$\begin{matrix}{I_{\gamma\lim}^{\prime} = \frac{T_{m\; 2}^{*}}{K_{1} \cdot I_{\delta}^{*}}} & (26)\end{matrix}$Wherein, the motor torque constant (K 1) is represented by M·K Te.Further, as described above, since the torque constant (K Te) isrepresented by p·M/Lr, the motor torque constant (K 1) is thusrepresented by K 1=p·M 2/Lr. The motor torque constant (K 1) is apreviously set value by calculation or experiments.

The limit value correcting unit 215, as shown in equation (27), bymultiplying the γ-axis current limit value (I γlim′) with a functioncontaining the time constant (τ m) and the time constant (t φ), correctsthe γ axis current limit value (I γlim′) to calculate a γ-axis currentlimit value (I γlim).

$\begin{matrix}{I_{\gamma\lim} = {\frac{{\tau_{\phi}s} + 1}{{\tau_{m}s} + 1}I_{\gamma\lim}^{\prime}}} & (27)\end{matrix}$

Note that the correction process by the limit value correcting unit 215represents an approximate compensation process with respect to the rotorflux response and the torque response.

The exciting current limiting unit 216, by restricting on the excitationcurrent command value calculated by the excitation current limiting unit201 by the positive and negative γ-axis current limit value (±I γlim),calculates a γ axis current command value (I γ).

As described above, in the present embodiment, based on a command valuethat is compensated for by the flux response compensation unit 32, alimit value is calculated using the equation (25) or equation (26), andthe current command value which is not compensated by the flux responsecompensation unit 32 is restricted by the limit value. Thus, through thecompensation by the magnetic flux response compensation unit 32, and thecompensation by the excitation current compensation control unit 100 orthe torque current compensation control unit 200, whatever value thecurrent command value might assume, the output torque may approach theideal response of the torque command value.

The torque current limit value calculating unit 114 corresponds to the“second current limit value calculating means or device” of the presentinvention, while the torque current limiting unit 115 corresponds to the“second current command value limiting means or device” of the presentinvention, respectively.

The invention claimed is:
 1. A motor control device, comprising: acurrent command value calculating device configured to calculate a basiccurrent command value based on a torque command value input from theoutside and a rotation speed of a motor; a first compensation deviceconfigured to compensate for delay of a rotor flux response of the motorby amplifying the basic current command value; a first current commandvalue limiting device configured to restrict a post-compensation currentcommand value by a first current limit value; a second compensationdevice configured to calculate, based on an amplified current commandvalue calculated by the first compensation device and the first limitedcurrent command value calculated by the first current command valuelimiting device, a compensation value for the amplified current commandvalue; an adding device configured to add the amplified current commandvalue and the compensation value to calculate the post-compensationcurrent command value; and a motor control device configured to controlthe motor based on the first restricted current command value, thesecond compensation device being configured to calculate, as thecompensation value, a portion of the amplified current command valuewhich has been subject to the restriction by the first current limitvalue.
 2. The motor control device as claimed in claim 1, wherein thesecond compensation device is configured to integrate a differencebetween the amplified current command value and the first current limitvalue to calculate the compensation value.
 3. The motor control deviceas claimed in claim 1, wherein the second compensation device isconfigured to multiply an integrated value obtained by integrating thedifference between the amplified current command value and the firstcurrent limit value with a predetermined gain to calculate thecompensation value.
 4. The motor control device as claimed in claim 1,wherein the second compensation means device is configured to rest thecompensation value based on a difference between an output torque of themotor and the torque command value.
 5. The motor control device asclaimed in claim 1, wherein the second compensation means device isconfigured to rest the compensation value based on a difference betweenthe basic current command value and the amplified current command value.6. The motor control device as claimed in claim 1, further comprising: asecond current limit value calculating device configured to calculate asecond current limit value based on the first restricted current commandvalue and the torque command value; and a second current command valuelimiting device configured to restrict the current command value by thesecond current limit value, the first compensation device configured tocalculate the amplified current command value by compensating for thebasic current command value with respect to one of the current commandvalues of the excitation current command value and the torque currentcommand value included in the current command value of the motor, thesecond current limit value calculating device being configured tocalculate a rotor flux estimation value of the motor based on the firstrestricted current command value to calculate the second current limitvalue by dividing the torque command value by a multiplication value ofa gain determined by a motor constant and the rotor flux estimationvalue, the second current command value limiting device being configuredto calculate the second restricted current command value by restrictingby the second current limit value on the basic current command value ofthe excitation current command value or the torque current commandvalue, which is not compensated by the first compensation device, andthe motor control device being configured to control the motor based onthe second restricted current command value.
 7. The motor control deviceas claimed in claim 1, further comprising: a first current limit valuecalculating device configured to calculate the first current limitvalue, the first compensation device being configured to compensate forthe basic current command value of one of the excitation current commandvalue and the torque current command value contained in the currentcommand value of the motor to calculate the amplified current commandvalue, and wherein the first current limit value calculating devicebeing configured to estimate a current value of a current value which isnot compensated by the first compensation device based on the basiccurrent command value of the one of the excitation current command valueand the torque current command value, which is not compensated by thefirst compensation device and to calculate the first current limit valuebased the estimated current value.
 8. The motor control device asclaimed in claim 1, further comprising: a first current limit valuecalculating device configured to calculate the first current limitvalue, the first compensation configured to compensate for the basiccurrent command value of one of the excitation current command value andthe torque current command value contained in the current command valueof the motor, and the first current limit value calculating device beingconfigured to calculate the first current limit value based on thecurrent command value of the one of the excitation current command valueand the torque current command value, which is not compensated by thefirst compensation device and a maximum current limit value indicatingthe rated current of the motor, while satisfying the equation;I _(lim)=√{square root over ((I _(max))²−(I ^(a)*)²)} Wherein I_(lim)represents the first current limit value, I_(max) indicates the maximumcurrent limit value, I_(a) represents a current command value which isnot compensated by the first compensation device.
 9. A motor controlmethod, comprising: calculating a basic current command value based on atorque command input from the outside and a rotation speed of a motor;calculating an amplified current command value by amplifying the basiccurrent command value for compensating for delay of a rotor fluxresponse of the motor; calculating a post-compensation amplified currentcommand value by further compensating for the amplified current commandvalue; restricting the post-compensation amplified current command valueby a current limit value corresponding to the magnitude of the amplifiedcurrent command value; controlling the motor by a command valuerestricted by the current limit value, when the amplified currentcommand value is restricted by the current limit value, after theamplified current command value falls below the current limit value, theamount of the command value which has been subject to restriction by thecurrent limit value is added to the amplified current command value. 10.The motor control device as claimed in claim 2, wherein the secondcompensation device is configured to multiply an integrated valueobtained by integrating the difference between the amplified currentcommand value and the first current limit value with a predeterminedgain to calculate the compensation value.
 11. The motor control deviceas claimed in claim 2, wherein the second compensation device isconfigured to rest the compensation value based on a difference betweenan output torque of the motor and the torque command value.
 12. Themotor control device as claimed in claim 3, wherein the secondcompensation device is configured to rest the compensation value basedon a difference between an output torque of the motor and the torquecommand value.
 13. The motor control device as claimed in claim 2,wherein the second compensation device is configured to rest thecompensation value based on a difference between the basic currentcommand value and the amplified current command value.
 14. The motorcontrol device as claimed in claim 3, wherein the second compensationdevice is configured to rest the compensation value based on adifference between the basic current command value and the amplifiedcurrent command value.
 15. The motor control device as claimed in claim2, further comprising: a second current limit value calculating deviceconfigured to calculate a second current limit value based on the firstrestricted current command value and the torque command value; and asecond current command value limiting device configured to restrict thecurrent command value by the second current limit value, the firstcompensation device configured to calculate the amplified currentcommand value by compensating for the basic current command value withrespect to one of the current command values of the excitation currentcommand value and the torque current command value included in thecurrent command value of the motor, the second current limit valuecalculating device being configured to calculate a rotor flux estimationvalue of the motor based on the first restricted current command valueto calculate the second current limit value by dividing the torquecommand value by a multiplication value of a gain determined by a motorconstant and the rotor flux estimation value, the second current commandvalue limiting device being configured to calculate the secondrestricted current command value by restricting by the second currentlimit value on the basic current command value of the excitation currentcommand value or the torque current command value, which is notcompensated by the first compensation device, and the motor controldevice being configured to control the motor based on the secondrestricted current command value.
 16. The motor control device asclaimed in claim 3, further comprising: a second current limit valuecalculating device configured to calculate a second current limit valuebased on the first restricted current command value and the torquecommand value; and a second current command value limiting deviceconfigured to restrict the current command value by the second currentlimit value, the first compensation device configured to calculate theamplified current command value by compensating for the basic currentcommand value with respect to one of the current command values of theexcitation current command value and the torque current command valueincluded in the current command value of the motor, the second currentlimit value calculating device being configured to calculate a rotorflux estimation value of the motor based on the first restricted currentcommand value to calculate the second current limit value by dividingthe torque command value by a multiplication value of a gain determinedby a motor constant and the rotor flux estimation value, the secondcurrent command value limiting device being configured to calculate thesecond restricted current command value by restricting by the secondcurrent limit value on the basic current command value of the excitationcurrent command value or the torque current command value, which is notcompensated by the first compensation device, and the motor controldevice being configured to control the motor based on the secondrestricted current command value.
 17. The motor control device asclaimed in claim 4, further comprising: a second current limit valuecalculating device configured to calculate a second current limit valuebased on the first restricted current command value and the torquecommand value; and a second current command value limiting deviceconfigured to restrict the current command value by the second currentlimit value, the first compensation device configured to calculate theamplified current command value by compensating for the basic currentcommand value with respect to one of the current command values of theexcitation current command value and the torque current command valueincluded in the current command value of the motor, the second currentlimit value calculating device being configured to calculate a rotorflux estimation value of the motor based on the first restricted currentcommand value to calculate the second current limit value by dividingthe torque command value by a multiplication value of a gain determinedby a motor constant and the rotor flux estimation value, the secondcurrent command value limiting device being configured to calculate thesecond restricted current command value by restricting by the secondcurrent limit value on the basic current command value of the excitationcurrent command value or the torque current command value, which is notcompensated by the first compensation device, and the motor controldevice being configured to control the motor based on the secondrestricted current command value.
 18. The motor control device asclaimed in claim 5, further comprising: a second current limit valuecalculating device configured to calculate a second current limit valuebased on the first restricted current command value and the torquecommand value; and a second current command value limiting deviceconfigured to restrict the current command value by the second currentlimit value, the first compensation device configured to calculate theamplified current command value by compensating for the basic currentcommand value with respect to one of the current command values of theexcitation current command value and the torque current command valueincluded in the current command value of the motor, the second currentlimit value calculating device being configured to calculate a rotorflux estimation value of the motor based on the first restricted currentcommand value to calculate the second current limit value by dividingthe torque command value by a multiplication value of a gain determinedby a motor constant and the rotor flux estimation value, the secondcurrent command value limiting device being configured to calculate thesecond restricted current command value by restricting by the secondcurrent limit value on the basic current command value of the excitationcurrent command value or the torque current command value, which is notcompensated by the first compensation device, and the motor controldevice being configured to control the motor based on the secondrestricted current command value.
 19. The motor control device asclaimed in claim 6, further comprising: a first current limit valuecalculating device configured to calculate the first current limitvalue, the first compensation device being configured to compensate forthe basic current command value of one of the excitation current commandvalue and the torque current command value contained in the currentcommand value of the motor to calculate the amplified current commandvalue, and the first current limit value calculating device beingconfigured to estimate a current value of a current value which is notcompensated by the first compensation device based on the basic currentcommand value of the one of the excitation current command value and thetorque current command value, which is not compensated by the firstcompensation device and to calculate the first current limit value basedthe estimated current value.
 20. The motor control device as claimed inclaim 6, further comprising: a first current limit value calculatingdevice configured to calculate the first current limit value, the firstcompensation configured to compensate for the basic current commandvalue of one of the excitation current command value and the torquecurrent command value contained in the current command value of themotor, and the first current limit value calculating device beingconfigured to calculate the first current limit value based on thecurrent command value of the one of the excitation current command valueand the torque current command value, which is not compensated by thefirst compensation device and a maximum current limit value indicatingthe rated current of the motor, while satisfying the equation;I _(lim)=√{square root over ((I _(max))²−(I _(a)*)²)} Wherein I_(lim)represents the first current limit value, I_(max) indicates the maximumcurrent limit value, I_(a)* represents a current command value which isnot compensated by the first compensation device.